This invention relates to seals of the type used to seal hasps on enclosures such as vehicle doors, mail bags, and the like where the function of the seal is to detect pilferage.
Known seals of this type are often formed of a single piece of molded plastic, with a socket formed on one end of a strap and a shackle of small diameter extending from the other end of the strap, with said shackle being adapted for locking non-removable engagement when pulled through the socket. A seal of this type is disclosed and claimed in U.S. Pat. No. 4,001,919 issued Jan. 11, 1977. The seal of that patent has been found to be highly satisfactory in many applications, however the locking portions are difficult to mold accurately, and tolerance variations sometimes cause the seal to be less secure than desired. It would be desirable to have larger locking means, such as male and female snap fastener portions, however in many applications where such a seal is used, the aperture in the staple through which the seal is assembled is too small to allow a snap fastener portion to pass therethrough.
Such seals are usually provided with a weakened portion in the shackle, which is intended to break when attempts are made by an unauthorized person to open the seal. However it has been found that in some instances a seal which has been broken at the weakened portion can be re-assembled without leaving readily noticeable evidence of tampering by fusing the broken ends together by heating with a match, cigarette lighter or the like.